Here's yet another approach.
Consider the block of seven numbers (7n - 3), (7n - 2), (7n - 1), 7n, (7n + 1), (7n + 2), (7n + 3).
n = 1 will cover the numbers 4 to 10,
n = 2 will cover 11 through to 17, and so on.
Cubing the first one get you (7n)^3 - 3(3)(7n)^2 + 3(3)^2(7n) - 3^3.
The first three of those are divisible by 7 so any surplus mod 7 comes from the last term -27,
and that will be 1, ( -27 = (-4).7 + 1)
From the remaining six terms, the contributions come from -8, -1, 0, 1, 8, and 27.
These will be -1, -1, 0, 1, 1, and -1, so the total contribution for all seven numbers will be 1 -1 -1 + 0 +1 + 1 -1 = 0.
That will be the case for all complete blocks of seven.
It follows that the the only contributions to the final remainder will come from (each one cubed), 1, 2, 3 ,95,96,97,98,99, and 100.
Writing the final group of six numbers as (14.7 - 3), (14.7 - 2), (14.7 - 1), 14.7, (14.7 + 1) and (14.7 +2),
the contributions from these nine will be, 1, 8, 27, -27, -8, -1, 0, 1, 8 leading to remainders (mod 7), 1, 1, -1, 1, -1, -1, 0 1, 1,
for a final total of 2.
Tiggsy